92 New Owner. No manual yet. Have replaced Tstat, no water leak, coolant appears good (?) 212K orig radiator?

Symptoms: After car is cold, it warms up to near red area, then I frantically put heat on full blast, and it comes back down to normal and stays. Even if I drive for an hour, in traffic. Then I tried putting heat on full blast once it barely began to warm up, but it still climbed to terrifying level, until it backed off by itself.

What I'm thinking: clogged radiator, bad 'new' tstat, is there some temp sensor?

Actions? Any suggestions for back flushing a radiator? Does that mean flush it in the opposite direction than engine water flow? Can one just hook up the old garden hose, or do you need to insert an inline valve to hook the hose to? Which cleaners to use, how to do it without contaminating too much.

I haven't tried running it without a Tstat. I might try that first. Any suggestions would be appreciated. Thanks

sounds like a tsat... take it out, test it on the stove with a latee thermometer...

if its not that, i would guess temp sensor.... doesnt seem right that a clogged radiator would only affect cooling at startup.

radiators are cheap... www.radiatorbarn.com mine was just over 100 bucks for a 3-core HD...

I agree t-stat

You don't say what engine you have but I think this happens with some years of 4 cyl and is no big deal. If it's the 6 then somethings not right.

You might do a search and see what comes up.

deff sounds like the t-stat is too hot, or sticky. I know a lot of people have found that the cheapo parts store t-stats tend to have a high falure rate out of the box. Take it out and put it in near boiling water on the stove and see that it opens at the proper temp

May need a dual tsat. See below.
https://www.yotatech.com/forums/f116...s-fine-222937/

i bet he figured it out as this thread is about 5 years old.

I bet your right I was searching for somthing else when this came up my bad.

its good info for other people too man

thanks bro.

+1 that should take care of it



Sorry I did not realize this thread was so old....